This invention relates to methods and apparatus for sandblasting fiber optic substrates to create fiber optic illuminating devices.
Fiber optic substrates, including both plastic optical fiber filaments and other shaped bodies, can be made into illuminators by marring, piercing or abrading (hereafter collectively referred to as xe2x80x9cmarringxe2x80x9d) the surface of the substrates at various points along their length to cause a portion of the light applied to one or both ends of the substrates to be emitted from the marred and/or unmarred surface areas. Such substrates may be marred to create a specific illumination pattern and can be used, for instance, for ornamental lighting, display lighting, front lighting, splash lighting and/or back-lighting.
Increased surface marring results in increased light emission. Accordingly, the intensity of the light emitted along the length of the substrates can also be varied by varying the amount of surface marring.
It is generally known to mar fiber optic substrates by stamping, machining, molding or rolling the substrates to create a desired illumination pattern on the surface of the substrates. Also, it is generally known to blast the surface of substrates with sand, grit or beads (hereafter collectively referred to as sandblasting) to cause light to be emitted.
Sandblasting has the advantage of being a less expensive way of producing side-lighting substrates than other previously known methods. However, there is a need for better control of the sandblasting process in order to be able to create specific illumination patterns.
The present invention relates to various methods and apparatus for sandblasting the surface of fiber optic substrates to produce relatively inexpensive side-lighting products having a specific illumination pattern.
In accordance with the invention, the fiber optic substrates are pushed or pulled through a sandblasting machine having one or more sandblasting nozzles oriented to blast one or more sides of the substrates as the substrates pass through the machine. The sandblasting nozzles may be oriented perpendicular to the direction of movement of the substrates through the sandblasting machine or angled in any direction as desired.
In one invention embodiment, the sandblasting nozzles are intermittently operated to create intermittent light emitting areas along the length of the substrates as desired. In another invention embodiment, the substrates are passed through the sandblasting machine at a variable speed to produce a desired light output pattern, for instance, to produce even side-lighting.
In another invention embodiment, the speed of the substrates passing through the sandblasting machine is constant but the pressure of the blaster nozzles is regulated to vary the depth of penetration and/or number of abrasions of the marring to produce a desired light output pattern, for instance, even side-lighting.
In another invention embodiment, the speed of the substrates passing through the sandblasting machine and rate of operation and pressure of the blaster nozzles is constant but the distance between the blaster nozzles and the substrates is regulated in order to produce a desired light output pattern, for instance, even side-lighting.
In another invention embodiment, a relatively thin perforated plate is placed between the blaster nozzles and the substrates in order to produce a desired light output pattern, for instance, text, symbols, nomenclature or picture side-lighting.
In another invention embodiment, the substrates are washed or cleaned as they exit the sandblasting machine. Also, the sandblasted substrates are cut to any desired length.
In another invention embodiment, the sandblasted substrates are heat formed permanently into a desired shape, as a secondary operation. Also, other secondary operations such as light source attachment and/or reflective surface operations may be performed on the substrates as desired.
In another invention embodiment, where the fiber optic substrates are initially coiled, if straight side-lighting substrates are desired, the substrates may be passed through a heated chamber and then cooled to produce straight substrates.
These and other objects, advantages, features and aspects of the invention will become apparent as the following description proceeds.
To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter more fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but several of the various ways in which the principles of the invention may be employed.